1. Field of the Invention
The present invention relates to photographic printing systems. In particular, the present invention is a photographic reprint system in which dual indicia sensors are used to check for synchronization errors between the tabbed photographic film and the data being supplied from a storage medium.
2. Description of the Prior Art
In commercial photographic processing operations, very high rates of processing must be achieved and maintained in order to operate profitably. In order to permit efficient automatic processing, orders containing films of similar type and size are typically spliced together for developing. As many as 500 to 1,000 rolls of twelve, twenty, twenty-four and thirty-six exposure film of the same type and size may be spliced together for processing and printing purposes.
After developing, the photographic images contained in the film originals (generally negatives) are printed in an edge-to-edge relationship on a continuous strip of photosensitive paper by a photographic printer. The photographic printer causes high intensity light to be passed through the negative and imaged on the photographic print paper to expose the photographic emulsion layers of the paper. The print paper is subsequently processed to produce a print of the image contained in the negative.
This type of large-scale production is well suited to original or first-run production of photographic prints in which the film may be spliced to form a continuous roll. In the past, however, it has not been particularly well suited to production of reprints, where the customer has already received prints and has decided that he wishes to have additional prints made of certain negatives. Unlike first-run production, making of reprints has typically not been highly automated.
There are several reasons why reprints require special, less efficient handling. First, when reprints are ordered, the negatives generally have already been cut into short segments of three or four frames each, which are more difficult to handle than the longer film strips encountered in the first run production printing. Second, the customer may only desire reprints from one frame of a particular segment. This is unlike first-run production, in which a print is typically made from every printable negative on the strip. Third, often multiple prints rather than just a single print are desired from one or more negatives on a segment. Fourth, no extra non-printing area on the film is normally available to which a splice may be made. Fifth, reprints are requested from a much wider variety of film types than are typically encountered in first-run production. Sixth, color and/or density corrections may be required to produce a satisfactory print.
Because of these problems, making of reprints has often been handled on a manual or semi-automatic basis, and often on a different printer from the high speed first-run production printers on which it may be impossible to reproduce identical print color balance and density corrections. Also, dust and dirt from handling the negatives on a manual basis can degrade print quality. As a result, the quality of reprints often differs from first-run production prints. The lower quality of reprints in comparison to first-run production prints is a source of customer dissatisfaction.
In order to overcome some of the problems of making reprints, and to provide more efficient automated printing of reprints, systems have been developed in which the individual segments of negatives from which reprints are to be made are temporarily attached to a long paper strip or "tab". The "tabbing" of negatives to be reprinted is performed at a "preparation" or "order entry" station, where indicia (typically in the form of punched holes) are formed in the tab adjacent the frames of the negatives. These holes are used as frame location indicators and also provide frame status information. For example, in one system the number of holes may vary from one to four, with the first hole always indicating the frame location, while multiple holes provide the frame status information to allow the printer system to maintain synchronization of reprint data with the tabbed film material. In this system, two holes at a frame signify the end of a film strip, three holes at a frame signify the end of a customer order, and four holes at a frame indicate the end of a reel. In this type of system, a data entry device and a data storage device at the preparation station are used by the operator to store for each frame the number of holes in the tab, print quantity, density/color corrections, and setup number.
In a typical automated reprint system, a photographic printer includes sensors for sensing the indicia on the paper tab in order to sense the location of each frame to be printed. The data stored in the memory device for that particular frame is transferred to the photographic printer, and the required number of reprints, if any, from that frame are then produced.
One important requirement of this type of automated reprint system is that the data which is retrieved from the memory device correspond to the frame which is printed using that data. If loss of synchronization between the film advance and the data retrieval occurs, improper quantities of prints may be produced for all succeeding film frames. This can be extremely expensive both in terms of wasted materials and lost production time.